DAC /systems used for FM Radio?

[spirovious]

Hi,

I have been listening to my old aiwa walkman for a change.Whichever music I listened (Old or new songs),they sounds much much better than my music PC.
I found there is background detail & sound is fuller(many tracks).Every instruments sound realistic & not digital.How?

I have read that most of the FM studios use PC as main source device,but dont know how is the music actually played before transmission.
Which DAC/soundcard they do use?Even preamp?

Anyone knows about studios,please do reply.

Thanks.

 

[jls001]

DAC may not even be needed. There are two possible audio chains from FM studio to FM transmitter.

One: computer-based playout giving digital output in AES/EBU (single balanced XLR carrying both L and R). The digital audio is encoded (mostly to IP packets or G.703) so that it can travel over a leased line to the FM transmitter (most private FM transmitters are co-located in AIR or DDK premises as mandated by license condition, except some FM broadcasters who got license during Phase I of FM licensing like Mirchi, Midday, Red who are allowed, and continue to, operate in their own towers in many cities). At the Transmitter, a decoder decodes the received signal and makes it again AES/EBU. This can be fed directly to the audio processor, then FM modulator (exciter), then high power amplifier, then finally antenna.

Two: computer-based playout giving analog out through sound card, or a virtual sound driver, or through another device like (Axia's) Analog Node, fed to encoder (encoder can have different configurations and can accept AES/EBU or plain old analog on XLR). Then onwards, same as above.

So which is better? AFAIK, most broadcasters have warmly embraced digital, but some are realising now that feeding analog audio to the exciter gives more warmth.

To answer your specific query of which sound card is used, I think that depends from station to station but RME is fairly popular. Any sound card used in a professional recording studio can be used by radio stations also.

 

[spirovious]

Thanks for reply,my walkman is analoge & doesnt have digital tuner.So I was wondering,how beautiful sound I receive even after a long chain?
Why cant we get similar sound at home with digital equipments?
The sound of FM is close to analog recordings(even though they are digital files).

 

[jls001]

Thanks for reply,my walkman is analoge & doesnt have digital tuner.So I was wondering,how beautiful sound I receive even after a long chain?
Why cant we get similar sound at home with digital equipments?
The sound of FM is close to analog recordings(even though they are digital files).

Which station in Mumbai do you think sounds good? I am asking because I feel none sound good , at least to my ears (except may be one station which is forgivable). I am not talking about the kinds of songs played. I am referring only to the quality of the sound.

Just for info, FM audio band is cut off at 15.x kHz by design, and does not occupy the full 20kHz bandwidth. The audio is filtered steeply at 15 kHz and is gone at about 16 kHz. This is required since FM pilot occupies 19 kHz. And the audio signal must not interfere with the pilot signal.

The implication is that 15 kHz x 2 is only about 30 kHz (recall Nyquist sampling rate which is twice of highest frequency component). Compare that to the PCM sampling rate of 44.1 kHz. Even if one sends uncompressed PCM audio to the transmitter from the studio, it gets downsampled to about 32 kHz. And that's what we hear from our receivers. This of course does not mean that the studio should send some compressed audio (garbage in, garbage out applies strictly). The source should be the best that one can get.

 

[spirovious]

I like Radio mirchi, Radio City & Fever 104 much,with clean reception.Atleast on aiwa it sounds much better.

 

[novice-akki]

Even I feel SQ is better on FM (especially at night) thru my DAP when compared with the SQ of the same song (320 mps/ FLAC) played via same DAP, but wont say the same thing for daytime usually when I'm commuting to and from work. I prefer listening to music saved on DAP.

 

[quad]

Joshua, are you involved in the broadcasting side?

 

[spirovious]

Even I feel SQ is better on FM (especially at night) thru my DAP when compared with the SQ of the same song (320 mps/ FLAC) played via same DAP, but wont say the same thing for daytime usually when I'm commuting to and from work. I prefer listening to music saved on DAP.

I too listen mostly at night & there is no outside noise/disturbance,even transmission is good too.So I wanted to know which soundcard OR DAC they may be using for better sound out.
I asked one DJ on FB,but they even didn't understand what I was talking about.

 

[jls001]

Joshua, are you involved in the broadcasting side?

Yes, most of my working life Started out in telecom, moved to satellite television broadcasting, then to FM broadcasting.

 

[jls001]

I asked one DJ on FB,but they even didn't understand what I was talking about.

Hahahaha. Wrong person to ask.